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Area Forecast Discussion (AFD)

Issued by Brownsville/Rio Grande Valley, TX (BRO)

                            
000
FXUS64 KBRO 151944
AFDBRO

Area Forecast Discussion
National Weather Service Brownsville TX
244 PM CDT Sat Jun 15 2019

.SHORT TERM (Now through Sunday Night):Streamer showers showed up
this morning producing a few sprinkles over the Gulf waters, 
Laguna Madre and the eastern three counties. A repeat of this 
activity with with possible isolated daytime sea breeze convection
may occur through Sunday night as modest southerly flow, with a 
slight tropical tap, persist in between a mid-level low pressure 
trough over the Southern Plains and surface high pressure 
extending across the Gulf. Winds to decouple this evening with the
modest pressure gradient remaining in tact through Sunday as the 
mid-level trough will be slightly slower moving east maintaining 
breezy conditions Sunday. 

The moderate southerly flow and the added Gulf moisture to keep 
overnight lows slightly higher the next two nights lifting 
minimums into the upper 70s to lower 80s. As for high temperatures
Sunday, guidance temperatures may be underachieving by a few 
degrees and with more sun than clouds tomorrow bumped temperatures
up just by a few degrees over most guidance values. Heat indices 
to maintain recent values (103-109 degrees) with models guidance 
keeping dew points near seasonal normals.

.LONG TERM (Monday through Saturday): A modestly stable upper air
pattern will prevail through the period, with a lack of 
significant disturbances directly affecting the local area. 
Likewise, high pressure over much of the Gulf will result in 
summertime onshore breezes and Gulf moisture moving up from the 
south. Winds will strengthen a bit Wednesday through Saturday as a
series of shortwave troughs move out of the West and into the 
Plains, producing pressure falls upstream and a tighter gradient. 
Instability associated with an exiting short wave trough over East
Texas will provide the best chance of showers early in the 
forecast, but rain chances will be limited after that, at best. 
Similarly, partly cloudy skies on Monday will shift toward more 
sunshine as the week progresses. Already warm weather will trend 
hotter through the week. Heat index values of 107 to 112 degrees 
will be typical through midweek, but values in the mid teens will 
become more possible the latter half of the work week and into the
weekend.

&&

.MARINE:
Now through Sunday Night: Surface high pressure extending across
the Gulf of Mexico will continue to combine with a trough of 
lower pressure over West Texas and the Southern Plains. The peak 
of the pressure gradient occurs tonight into Sunday morning before
a gradually weakening occurs later Sunday. Winds and seas have 
been slightly below small craft advisory levels so far this 
afternoon but should meet criteria over the Gulf waters tonight so
will maintain the advisory there. On the Laguna, may drop the SCA
and replace with SCEC for the afternoon marine package. SCEC is 
anticipated for both the Laguna and Gulf waters Sunday. 

Monday through Thursday night...Moderate to fresh southeast to 
south winds and moderate seas will prevail through the period. 
Small craft should exercise caution to low end small craft 
advisory conditions will be possible on Monday and then again 
Wednesday night through Thursday night.

&&

.PRELIMINARY POINT TEMPS/POPS...
BAYVIEW/PORT ISABEL  81  92  80  91 /  20  20  20   0 
BROWNSVILLE          81  94  80  93 /  20  20  20  10 
HARLINGEN            79  95  79  94 /  10  20  10  10 
MCALLEN              79  97  80  97 /   0  10  10   0 
RIO GRANDE CITY      78 100  79 101 /   0  10  10   0 
SOUTH PADRE ISLAND   81  86  81  86 /  10  20  20  20 

&&

.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 7 PM CDT this evening for 
     GMZ130-132-135.

     Small Craft Advisory until 7 AM CDT Sunday for GMZ150-155-170-
     175.

&&

$$

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